Species Snapshot
- Species Name: Sewellia lineolata
- Common Names: Reticulated hillstream loach
- Size: Up to 2.5 inches
- Lifespan: 5-8 years
- Native Distribution: South, Southeast, and East Asia
A group of just over 200 species, hillstream loaches or river loaches belong to the family Balitoridae. They’re found in well-oxygenated, fast-flowing bodies of water throughout South, Southeast, and East Asia and have recently gained popularity in the aquarium hobby.
As the popularity of hillstream loaches continues to grow, these unique algae eaters are becoming more readily available. There is still a great deal of conflicting information out there about their care, however, so it’s important to research the particular species you plan to keep before you commit.
To help you decide whether the hillstream loach may be a good fit for your aquarium, here’s some general information about how long do hillstream loaches live and their care.
Anatomy and Appearance
The term loach describes a highly diverse group of freshwater, bottom-dwelling fish found throughout Eurasia and northern Africa. Some exhibit long, eel-like bodies while others are stout-bodied. Hillstream loaches are easily identified by their wide ventral fins that fan out on either side of their bodies. These fins enable them to cling to the rocks in fast-flowing bodies of water.
There are over 200 species of hillstream loach, but the most popular in the aquarium hobby is the reticulated hillstream loach (Sewellia lineolata). This species grows up to 2.5 inches in length and exhibits a dark brown or olive-green coloration, dotted with white or light-yellow spots.
When viewed from above, hillstream loaches have an almost butterfly-like shape. Underneath their bodies, they have a small suckermouth. Their gill slits are located on the underside of the body as well.
Ideal Aquarium Setup
Though still relatively new in the aquarium hobby, hillstream loaches have been known to adapt to a range of aquarium setups. Their native habitat is marked by clear, highly oxygenated, fast-flowing water but water parameters may fluctuate with heavy rainfall. Regardless of the specifics of your tank setup, hillstream loaches appear to prefer high water quality and a relatively stable pH.
Tank Size
Hillstream loaches are fairly small fish, growing to an average of 2 to 2.5 inches in length. They’re best kept in small colonies of three or more, however, so start with a tank large enough to accommodate the full size of your colony. Long tanks are preferable to tall tanks with a minimum volume of 20 gallons.
Water Parameters
The hillstream loach appears to adapt well to a range of tank conditions, but it’s generally best to keep parameters within the tank as stable as possible. These fish will accept temperatures ranging from 65°F to 80°F. Just keep in mind that higher temperatures may require additional oxygenation and the fish may be more susceptible to stress and illness.
The ideal water parameters for hillstream loaches are:
- Temperature: 65°F to 80°F
- pH Level: 6.5 to 7.8
- GH: 10-20 dGH
- KH: 10-15 dKH
Proper filtration is key in a tank for hillstream loaches. Choose a type of filter that creates some degree of water flow—a hang-on-back or cannister filter may be ideal. Sponge filters are beneficial for additional biological filtration but may not be adequate as a sole source of filtration. You may even need to install an additional powerhead if your hillstream loaches crave a higher degree of water flow.
Tank Décor
Hillstream loaches are best kept in established aquariums that provide plenty of surfaces from which they can scrape algae. Planted tanks work well, especially when decorated with driftwood and rockwork. Arrange the tank with plants to provide plenty of hiding places if you plan to keep a group of hillstream loaches together. This will help reduce aggression levels.
In terms of tank décor, the most important consideration for hillstream loaches may be the substrate. They spend a lot of time cruising along the bottom of the tank, so a soft, fine substrate like sand may be best. Think about the color of your substrate as well—hillstream loaches may stand out best against a dark-colored substrate.
Diet and Feeding
In the wild, hillstream loaches feed on algae as well as small crustaceans and other organisms that live along the river bottom. In the home aquarium, they’ll act as algae eaters but will need supplemental food. Offer your hillstream loaches sinking algae wafers and blanched vegetables as well as fresh or frozen foods like spirulina brine shrimp.
Temperament and Tank Mates
Hillstream loaches generally get along well with peaceful community fish of similar size and temperament. They spend most of their time along the bottom of the tank or cruising across plants and other surfaces, scraping algae. This being the case, they may do well with top feeders and schooling fish that tend to occupy the middle strata of the tank.
Avoid keeping your hillstream loaches with large, boisterous, or carnivorous tank mates. Hillstream loaches remain fairly small, so they may become prey to larger fish like cichlids. They can, however, get along with invertebrates like freshwater dwarf shrimp or snails.
Breeding Hillstream Loaches
In an established aquarium that provides plenty of natural food sources and cover, a colony of hillstream loaches may breed with little intervention. It can be difficult to sex hillstream loaches until they become fully mature at 5 to 8 months, so starting with a sizeable colony is generally the best method.
Male hillstream loaches typically grow larger than females and have more noticeable coloration. Offering a colony of mature hillstream loaches a varied diet of rich foods may help encourage breeding behavior. Spawning usually occurs over flat surfaces in the tank—the female deposits her eggs and the male follows along behind to fertilize them.
Because adult hillstream loaches may consume their eggs, it’s best to remove the adults after spawning. The eggs generally hatch after 2 to 4 days and, about a week later, the fry will become free swimming. Hillstream loach fry can be fed very small fresh foods like baby brine shrimp or daphnia.
While there is still plenty more to be learned about hillstream loaches, these beautiful fish can make an attractive and functional addition to an established planted aquarium. Just be sure the tank provides plenty of algae and places to hide and keep the water as clean as possible.
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